What is the best course of treatment for a patient with suspected diabetic ketoacidosis (DKA) or euglycemic DKA, who has been kept NPO (nothing by mouth) for approximately 20 hours for surgery and has not had ketone testing?

Management of Suspected DKA/Euglycemic DKA in NPO Patient Without Ketone Testing

Immediately obtain ketone testing (preferably serum β-hydroxybutyrate) and simultaneously begin aggressive fluid resuscitation with isotonic saline while awaiting results, as the 20-hour NPO period combined with surgical stress creates high risk for euglycemic DKA that can be missed without ketone measurement. 1, 2

Immediate Diagnostic Workup

Critical laboratory tests to obtain immediately:

• Serum β-hydroxybutyrate (preferred over urine ketones) - this is the gold standard for DKA diagnosis and monitoring 1, 3
• Arterial or venous blood gas (venous pH is typically 0.03 units lower than arterial) 1, 3
• Serum electrolytes with calculated anion gap 1
• Blood glucose, serum bicarbonate, BUN/creatinine 1, 3
• Complete blood count if infection suspected 1

Why ketone testing is non-negotiable: The 20-hour NPO period creates a perfect storm for euglycemic DKA - prolonged fasting combined with surgical stress increases counter-regulatory hormones (glucagon, catecholamines, cortisol) that drive ketogenesis even with normal glucose levels 4, 5, 6. Without ketone measurement, you will miss this diagnosis entirely since glucose may be <250 mg/dL or even normal 2, 5.

Diagnostic Criteria to Confirm

Standard DKA criteria (American Diabetes Association):

• Blood glucose >250 mg/dL
• Arterial pH <7.3
• Serum bicarbonate <15 mEq/L
• Presence of ketonemia or ketonuria 1

Euglycemic DKA criteria:

• Blood glucose <200-250 mg/dL (or even <11 mmol/L)
• pH <7.3, bicarbonate <15 mEq/L
• Elevated serum ketones (β-hydroxybutyrate >3.0 mmol/L)
• Anion gap >12 mEq/L 2, 5, 6

Initial Management While Awaiting Ketone Results

Start aggressive fluid resuscitation immediately - do not wait for ketone results:

• Begin isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in first hour) 1, 3, 2
• This restores circulatory volume, improves tissue perfusion, and improves insulin sensitivity 1

Hold insulin therapy initially if:

• Serum potassium <3.3 mEq/L - aggressively replace potassium first to prevent life-threatening arrhythmias 1
• Glucose is normal or low-normal and you're awaiting ketone confirmation 2, 7

Treatment Protocol Once DKA/Euglycemic DKA Confirmed

For Standard DKA (glucose >250 mg/dL):

• Continuous IV regular insulin at 0.1 units/kg/hour 1, 3
• Target glucose decline of 50-75 mg/dL per hour 1
• When glucose reaches 200-250 mg/dL, switch to 5% dextrose with 0.45-0.75% saline while continuing insulin 1, 2

For Euglycemic DKA (glucose <250 mg/dL):

This requires modified protocol:

• Start dextrose-containing fluids (5-10% dextrose) immediately with isotonic saline 2, 6, 7
• Delay insulin infusion until glucose rises above 250 mg/dL, OR start lower-dose insulin (0.05-0.1 units/kg/hour) with concurrent dextrose 2, 7
• Higher dextrose concentrations (10-20%) may be needed to facilitate the large insulin doses required to correct severe acidosis 6
• Critical pitfall: Inadequate carbohydrate administration alongside insulin perpetuates ketosis in euglycemic DKA 2

Electrolyte Management:

• Once urine output confirmed and K+ >3.3 mEq/L, add 20-30 mEq/L potassium (2/3 KCl, 1/3 KPO₄) to IV fluids 1
• Target serum potassium 4-5 mEq/L throughout treatment 1
• Check electrolytes every 2-4 hours 1, 3
• Do NOT give bicarbonate if pH >6.9-7.0 - multiple studies show no benefit and may worsen ketosis, cause hypokalemia, and increase cerebral edema risk 1, 3, 2

Monitoring for Resolution

Continue insulin infusion until ALL criteria met:

• pH >7.3
• Serum bicarbonate ≥18 mEq/L
• Anion gap ≤12 mEq/L
• Glucose <200 mg/dL 1, 3, 2

Do NOT stop insulin when glucose normalizes - this is the most common cause of persistent or worsening ketoacidosis 1, 3. Instead, add dextrose and continue insulin until acidosis resolves 1, 2.

Transition to Subcutaneous Insulin

When DKA resolved and patient remains NPO:

• Continue IV insulin and fluid replacement 1
• Supplement with subcutaneous regular insulin as needed 1

When patient able to eat:

• Administer basal insulin (glargine or detemir) 2-4 hours BEFORE stopping IV insulin to prevent rebound ketoacidosis 1, 3, 2
• Start multiple-dose regimen with rapid-acting and long-acting insulin 1, 3

Special Consideration: SGLT2 Inhibitor Risk

If patient on SGLT2 inhibitors:

• These medications dramatically increase euglycemic DKA risk, especially peri-operatively 4, 1
• Risk is higher with emergency surgery (1.1%) versus elective surgery (0.17%) 4
• SGLT2 inhibitors should be discontinued 3-4 days before planned surgery 4, 1
• Even with 72+ hour cessation, postoperative ketoacidosis can still occur 4
• Do NOT restart until patient is metabolically stable and eating normally 1

Critical Pitfalls to Avoid

• Missing euglycemic DKA by not checking ketones - the NPO period and surgical stress make this highly likely 2, 5
• Starting insulin in euglycemic DKA without adequate dextrose - perpetuates ketosis and causes hypoglycemia 2, 6, 7
• Stopping insulin when glucose normalizes - leads to persistent acidosis 1, 3
• Inadequate potassium monitoring/replacement - total body potassium depletion is universal in DKA despite initial levels 1
• Premature discontinuation of IV insulin without prior basal insulin - causes rebound hyperglycemia and ketoacidosis 1, 3